Are you asking "WTF is PayPal"?
It is just an intermediary service which allows individuals
and businesses to make payments over the Web. You want to buy
something on E-Bay, you tell paypal to pay $199 to the owner....
they take care of getting $199 to the owner they charge
$199 to your credit card (plus a fee I think........this is
apriori as I have never used it).

I've heard before that things are a little gray once disputes
occur. For example......suppose you get stiffed (product does not show).
You take the problem up with your credit card company. Credit card company puts the appropriate credit to your account and takes it up with PayPal. Paypal pays up. Two weeks later, PayPal then sends you a separate invoice for $199 +
charges. Do you HAVE to pay? What are your rights?

(Sorry if I misunderstood your post/question).

To be honest I thought they were "legit" and reliable.
Your post was an eye opener for me.